The present invention relates to an ozone processing apparatus for a semiconductor processing system, which is used for subjecting a target substrate, such as a semiconductor wafer, to a process, such as reformation or oxidization, using ozone. The term xe2x80x9csemiconductor processxe2x80x9d used herein includes various kinds of processes which are performed to manufacture a semiconductor device or a structure having wiring layers, electrodes, and the like to be connected to a semiconductor device, on a target substrate, such as a semiconductor wafer or an LCD substrate, by forming semiconductor layers, insulating layers, and conductive layers in predetermined patterns on the target substrate.
In the processes of manufacturing semiconductor devices, activated oxygen atoms, i.e., oxygen radicals, are used, for example, when a thin film of, e.g., tantalum oxide (TaOx), disposed on a target substrate, such as a semiconductor wafer, is subjected to reformation. In this case, ozone (O3) is generated in an ozone generating unit and is activated by, e.g., an ultraviolet (UV) lamp, so that oxygen radicals to be used are generated.
FIG. 5 is a schematic view showing a conventional ozone processing apparatus for performing a reforming process. As shown in FIG. 5, the apparatus includes an ozone generating unit 10 and a reforming processing unit 20 connected to each other through a stainless steel piping line 15. The ozone generating unit 10 has a casing 14, in which an ozone generator 11, an ozone densitometer 12, and a pressure regulator 13 are disposed. On the other hand, the processing unit 20 has a process chamber 21, in which a worktable 23 is disposed for supporting a wafer W thereon. Above the process chamber 21, an UV lamp 22 is disposed, for radiating ultraviolet rays into the process chamber 21. A vacuum pump 24 is connected to the bottom of the process chamber 21 through a piping line.
In this apparatus, first, a raw material gas formed by mixing oxygen gas and nitrogen gas with each other is supplied to the ozone generator 11, where Radio Frequency (RF) high power is applied to the raw material gas to generate ozone gas. Then, the ozone gas, i.e., the process gas, is sent to the process chamber 21 through the piping line 15. In the process chamber 21, the ozone gas is activated by ultraviolet rays from the UV lamp 22 to generate oxygen atoms, i.e., oxygen radicals, with which the wafer W on the worktable 23 is processed. During this process, the interior of the process chamber 21 is exhausted by the vacuum pump 24.
In the ozone processing apparatus shown in FIG. 5, however, there is a problem in that the wafer W and/or a thin film thereon are contaminated by compounds of metals, such as chromium and iron, which seem to be derived from constituent materials of the piping line 15, the process chamber 21, and so forth. Such metal compounds, even in small amounts, can be serious causes of degrading the quality of semiconductor devices, as the semiconductor devices are smaller and thinner.
An object of the present invention is to provide an ozone processing apparatus, which can suppress the occurrence of metal contamination in a target substrate.
According to a first aspect of the present invention, there is provided an ozone processing apparatus for a semiconductor processing system, comprising:
an airtight process chamber;
a support member disposed in the process chamber and configured to support a target substrate;
an exhaust system configured to exhaust the process chamber;
a process gas supply line connected to the process chamber;
an ozone generator connected to the process gas supply line and configured to supply an ozone-containing gas through the process gas supply line into the process chamber;
a raw material gas supply line connected to the ozone generator;
an oxygen source connected to the raw material gas supply line and configured to supply oxygen gas through the raw material gas supply line into the ozone generator;
a branch line extending from the process gas supply line and arranged not to be connected to the process chamber;
a densitometer disposed on the branch line and configured to measure ozone concentration of the ozone-containing gas; and
a controller configured to control the ozone generator with reference to a measured value of the ozone concentration measured by the densitometer.
According to a second aspect of the present invention, there is provided an ozone processing apparatus for a semiconductor processing system, comprising:
an airtight process chamber;
a support member disposed in the process chamber and configured to support a target substrate;
an exhaust system configured to exhaust the process chamber;
a process gas supply line connected to the process chamber and made of a non-metallic material;
an ozone generator connected to the process gas supply line and configured to supply an ozone-containing gas through the process gas supply line into the process chamber;
a raw material gas supply line connected to the ozone generator;
an oxygen source connected to the raw material gas supply line and configured to supply oxygen gas through the raw material gas supply line into the ozone generator;
an envelope airtightly surrounding the process gas supply line such that a gap space is formed between the process gas supply line and the envelope;
a drying system configured to supply a heated dry gas into the process gas supply line, thereby drying the process gas supply line from an inner surface; and
a ventilation system configured to ventilate the gas space.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.